Diversity of ultraviolet reflection pattern in Arachis flowers

Authors: LEVINSON, C - University Of Georgia; CHU, Y - University Of Georgia; LEAL-BERTIOLI, S.C.M. - University Of Georgia; STALKER, H - North Carolina State University; Holbrook, Carl - Corley; GAO, D - University Of Georgia; OZIAS-AKINS, P - University Of Georgia

Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/8/2022
Publication Date: 6/30/2022
Citation: Levinson, C.M., Chu, Y., Leal-Bertioli, S., Stalker, H.T., Holbrook Jr, C.C., Gao, D., Ozias-Akins, P. 2022. Diversity of ultraviolet reflection pattern in Arachis flowers. Peanut Science. 49:12-25. https://doi.org/10.3146/0095-3679-492-PS22-1.
DOI: https://doi.org/10.3146/0095-3679-492-PS22-1

Interpretive Summary: Learning more about what attributes to flower attractiveness of various crops, including attractiveness caused by area and pattern of UV absorption, can lead to better decision-making regarding wild pollinator recruitment for crop fields. Increasing plant biodiversity in urban and agricultural landscapes is one way to increase wild bee abundance and diversity. Ornamental Arachis species should be evaluated for promoting wild bee abundance and diversity in urban landscapes while high-flowering peanut cultivars should be evaluated for use as cost-effective border crops or floral strips for pollinator recruitment for crop fields. This study is the first to look at UV nectar guides in Arachis and found that nectar guides of various sizes are present in both wild Arachis species, allotetraploids, and the cultivated peanut species. However, a wide knowledge gap about nectar guides in crops, particularly those with bilaterally symmetric flowers, still exists, and this study is only one step towards narrowing this gap.

Technical Abstract: A large portion of global agriculture is dependent on insect pollination, especially by bees. Yields of insect-pollinated crops are often managed by the addition of honeybees (Apis mellifera) to increase pollination, yet wild bee species (Bombus spp.) also increase pollination and fruit set for many globally important crops. Plant biodiversity within and surrounding crop fields can attract wild bee species and increase pollination in those fields. Peanut is an important global food crop known to attract honeybees and wild bee pollinators, and current breeding efforts include introgression of desirable alleles from wild Arachis species into cultivated peanut. Some wild Arachis species derived breeding materials have been documented to have early flowering, high flowering throughout the growing season, and large flowers as compared to cultivated peanut, which can increase benefits for bees. However, the presence and diversity of UV nectar guides to aid bees in detection of flowers and orientation after landing have not been studied in Arachis. This study sought to document the presence and diversity of nectar guides in two A. hypogaea genotypes, two breeding lines, 8 wild Arachis species, 19 unique allotetraploids, and four BC1F3lines. All Arachis genotypes studied had UV nectar guides and genotype was a significant indicator of flower size and nectar guide size according to the following parameters: banner area, area of UV absorption on the banner (abaxial and adaxial), area of UV absorption on the banner as a percentage of total banner area (abaxial and adaxial), left wing area, area of UV absorption on the left wing (abaxial and adaxial), and area of UV absorption on the left wing as a percentage of total left wing area (abaxial and adaxial). Further studies are needed to evaluate the use of ornamental Arachis species and floriferous peanut cultivars for promoting wild bee abundance and diversity in urban landscapes and for use as cost-effective border crops for pollinator recruitment.